In an optical module having a plurality of laser diodes that are hermetically enclosed in a package and include a laser diode having an oscillation wavelength of not more than 550 nm, a dust collection effect such as described in Patent Document 1 (Japanese Unexamined Patent Publication No. 2004-233885) is known to take place. The dust collection effect is such that contaminants remaining inside the package adhere to, for example, emission end faces of the laser diodes. The laser diode having the oscillation wavelength of not more than 550 nm performs high-energy emission, so that the above dust collection effect is noticeable. When the dust collection effect takes place, output of the laser diode is degraded, thus resulting in reduced reliability of the optical module. Sources of contamination that cause the dust collection effect include a resin curing adhesive (for example, ultraviolet curable resin) that is used for bonding an optical component to another component. In a technique described in the Patent Document 1, because of not becoming a source of contamination, flux-free solder or an adhesive not containing Si-based organic substances is used to bond an optical component to another component for the purpose of reducing the above dust collection effect.